Toyohara A, Shigenaka Y, Mohri H
J Cell Sci. 1978 Aug;32:87-98. doi: 10.1242/jcs.32.1.87.
In the heliozoan, Echinosphaerium nucleofilum strain MA, cold temperature (2 degrees C) induced axopodial retraction to about 36% of the initial length after 3 h. By electron microscopy, it was found that such axopodial shortening is accompanied by degradation of axonemal microtubules (25 nm in diameter), followed by the appearance of macrotubles (37 nm in diameter) and filamentous structures (14 nm in diameter) of a tubular and twisted appearance. All of these structures (microtubules, macrotubules and filamentous structures) were found to be depolymerized completely by applying 10 mM colchicine for 1-2 h, and to be replaced by regions with low electron density. Axopodial re-extension was induced rapidly by returning the cold-treated organisms to room temperature (20 degrees C). At a very early stage of axopodial re-extension, the filamentous structures were often observed to be continuous with the macrotubules. At a late stage of axopodial re-extension, the reforming axoneme was composed only of normal microtubules, while the macrotubules and filamentous structures had disappeared. On the basis of these results, the processes of disintegration and reformation of microtubules are discussed.
在太阳虫类的核丝棘球虫MA菌株中，低温（2℃）处理3小时后，轴足收缩至初始长度的约36%。通过电子显微镜观察发现，这种轴足缩短伴随着轴丝微管（直径25nm）的降解，随后出现了大微管（直径37nm）和呈管状且扭曲的丝状结构（直径14nm）。通过施加10mM秋水仙碱1 - 2小时，发现所有这些结构（微管、大微管和丝状结构）完全解聚，并被低电子密度区域所取代。将经低温处理的生物体恢复至室温（20℃）可迅速诱导轴足重新伸展。在轴足重新伸展的非常早期阶段，常观察到丝状结构与大微管相连。在轴足重新伸展的后期，重新形成的轴丝仅由正常微管组成，而大微管和丝状结构消失。基于这些结果，对微管的解体和重新形成过程进行了讨论。
